Slayer or Demon?
by RoseWithThorns
Summary: The year after her death at the hands of the Master was a year that Buffy Summers, The Slayer will never forget. That was the year she gained a brother and another family after she briefly lost her life. It was also the year in which she had to answer a simple question. Was she the Slayer or a demon? Or both?
1. Prologue

Prologue

Disclaimer: I don't own YYH or Buffy the Vampire Slayer.

"English"

" _Japanese"_

' **Thoughts'**

It was a warm evening and most of the gang had gathered at Genkai's temple for an announcement. Yusuke and Keiko announced to the gang that they were going to have a baby. Later that night, Kuwabara found Yusuke standing outside looking at the sky with a strange look on his face.

" _Something wrong, Urameshi?_ " asked Kuwabara as he sensed that there was something going on with Yusuke

Yusuke sighed before looking back at Kuwabara and replying " _No. I just can't shake the feeling that something bad has happened._ "

Unbeknown to Yusuke, his younger sister has just died half way around the world from him.

Died and then was brought back by a friend of hers. Her name was Buffy Summers or so she thought. Her name was really Elizabeth Urameshi, daughter of Atsuko Urameshi and Hank Summers, younger sister of Yusuke Urameshi, and Vampire Slayer.

The day after her death, Buffy left Sunnydale, California to spend the summer with her father, Hank in New York City. What should have been a fun and exciting summer filled with shopping and seeing the sights was instead tainted by the trauma of dying and living again, and the feeling of terror and helplessness. During this time she, unknowingly, was crying out for help in her very soul and someone half around the world heard her. This is where our story truly beings…

* * *

Nami: Well, it is a start and to a story that I never thought I would be able to write. I had planned to make this idea of Yusuke and Buffy being related (as siblings or cousins) into a challenge and maybe I still will. However, this prologue and the following chapter just kind of hit me, and I started to write out the story. In this story, Yusuke and Buffy are half-siblings with the same mother but different fathers. For this story, unlike in my story Triple Trouble in which it is the father, Atsuko Urameshi is the descendant of Raizen although she will never awaken her demon blood.


	2. Chapter 1: The Discovery

Chapter 1: The Discovery

Disclaimer: I don't own YYH or Buffy the Vampire Slayer.

"English"

" _Japanese"_

' **Thoughts'**

" _WHAT?!_ " was the shout heard through the doors that led to the office of Koenma, Prince of Spirit World. The ogres all shook their heads wondering what their boss had done now to anger Yusuke Urameshi, the officially former Spirit Detective. Little did they know that Koenma's news was about to shifted the scales and cause them more paperwork to file.

" _What do you mean that I have a little sister?_ " shouted Yusuke

Koenma, having known exactly how Yusuke would react to this news, was calm. He had had his panic attack much earlier when he had found out.

" _Technically you have a younger half-sister. Her name is currently Buffy Summers but legally in Japan, she is still Elizabeth Urameshi. Her father, Hank Summers, kidnapped her when she was only two months old and took her to the United States._ "

Yusuke just stared at Koenma in shock.

Koenma continued " _That whisper you've been hearing everywhere is her calling out for help_ …"

Yusuke interrupted, enraged, " _Where is she?_ " thinking that no one was going to hurt his newfound sister.

" _Right now she is heading back the Hellmouth or as most people call the place, Sunnydale, California. She is not currently in danger._ "

Koenma was saying that last sentence just as Yusuke was opening the doors.

" _Then why is she calling for help?_ " Yusuke asked through clinched teeth

Here Koenma hesitated and said with a whine " _Maybe you sit down first._ "

Yusuke slammed the doors back shut and glared at Koenma

" _Why?_ "

Koenma signed and decided to soldier on " _She died about 3 months ago for a few minutes._ "

Koenma watched as Yusuke quickly paled and sat down hard on the floor and continued quickly " _But a friend of hers was able to bring her back by CPR. Her death was very traumatic to her and the death was able to slightly wake up her dormant demon blood. This awakening caused a small connection to form between her and you._ "

" _So the whispers are due to this connection?_ " asked Yusuke

Koenma nodded " _Yes, exactly. Her recent and brief death traumatized her. Especially since there was a prophecy involved._ "

Yusuke glared at him and asked " _What prophecy?_ "

Koenma winced again and answered " _The prophecy that said that the Slayer would die at the hands of The Master and her blood would be his key out of his prison._ "

At Yusuke's look of pure rage, Koenma started to fear for his life a little bit.

" _A Slayer of what? Where is this Master?_ " Yusuke asked through clinched teeth

" _A Vampire Slayer and The Master died that same night by her hand._ " Koenma continued "' _Into every generation there is born a girl who alone will stand against the darkness. She is the Slayer.' That is the story anyway that the Watchers give Slayers when they are called. The Watchers is a group that watches over the Slayer line and trains them. Not very well though._ " Koenma half murmured that last sentence but Yusuke heard it anyway.

" _I've heard enough Toddler._ "

Koenma sighed " _You're going to the Hellmouth, aren't you?_ "

At Yusuke's nod, Koenma sighed again and reached for a folder on his desk.

" _You'll want to read this before you go and talk to the others._ " he said as he handed Yusuke the folder " _It tells the summary of her life so far and what you can expect on the Hellmouth. I warn you Yusuke the story is not a pretty one and the dangers she will face in life will be great. You cannot protect her from her destiny._ "

" _No._ " Yusuke said as he took the folder from Koenma and walked out " _I might not be able to protect her from her destiny, but I sure as hell can prepare her for it._ "

* * *

Nami: Okay, I have no idea where the ending of this chapter came from. And I would like to take this time to inform the readers that the time frame is set after the Yu Yu Hakusho episodes ended. All of the characters (except those from the Spirit World and Demon World) have grown up and matured including Yusuke and Kuwabara. Don't worry there will still be plenty of moments where they act like they did in the show because that is a part of their personalities. However, they are more understanding of the world and that there are some things in this world you cannot stop only prepare for. I would also like to point out that this story will be taking place mostly according to Buffy's timeline and therefore will be happening mostly in Sunnydale with moments here and there elsewhere.


	3. Chapter 2: Family is Family

Chapter 2: Family is Family

Disclaimer: I don't own YYH or Buffy the Vampire Slayer.

"English"

" _Japanese"_

' **Thoughts'**

* * *

-Last time-

" _No._ " Yusuke said as he took the folder from Koenma and walked out " _I might not be able to protect her from her destiny, but I sure as hell can prepare her for it._ "

* * *

-This time -

Yusuke read the file in a quiet area of Spirit World before returning to Koenma's office.

He said to Koenma " _I'll be back in 3 hours and there'll be a portal waiting to take me to Sunnydale._ "

Koenma shook his head stating " _Sorry Yusuke, but no portals. This is a Human World matter technically so for legal reasons, you'll need to take a plane instead._ "

Yusuke glared at Koenma and demanded " _Then, get me on the first plane to California. And call the team together on my orders, I'll need them to keep Keiko and this side of the portal safe while I'm gone._ "

Koenma sighed and stated " _I had the feeling you would say that. Your plane leaves tomorrow morning at 2 am sharp. That was the earliest I could get at such short notice. There will be a car waiting for you in Los Angeles. Please try not to damage it._ "

Yusuke said " _No promises._ " as he headed out the doors to go back to human world.

* * *

-Time skip-Meeting area in the woods by Genkai's temple-

" _Guys, I'm leaving Japan for a while. Watch over Keiko while I'm gone._ " Yusuke said to Kurama, Hiei, and Kuwabara.

" _Urameshi what gives? Is why you called this meeting?!_ " shouted Kuwabara upset by Yusuke's apparent abandonment of Keiko and their unborn baby

" _Why?_ " questioned Kurama knowing there was something more going on here

Yusuke signed before speaking again " _It's important. Koenma found something_ …"

Kuwabara interrupted " _Another 'end of the world' situation?_ "

Hiei glared at him for the interruption.

Yusuke chucked lightly and said " _Not at the moment. Koenma found out that I have a little sister, technically half-sister. I'm going to visit her and see what I can do to help her situation._ "

" _Can't you bring her back here?_ " asked Kurama, his mind racing

" _Can't. Koenma says she has to remain where she is for most of the time to prevent the world from ending there. Hiei, Kurama ever heard of 'the Slayer'?_ "

Hiei snorted in dismissal stating " _A myth. A human girl said to be empowered with a very low level demon's abilities who fights against vampires and other low life demons._ "

Yusuke grinned at Hiei " _Not a myth actually. And my sister is the current one charged with guarding the entrance to the current active Hellmouth in Sunnydale, California._ "

Kurama shook his head, lightly laughing, before saying " _Only you Yusuke would be related to someone nearly everyone considers a myth._ "

Yusuke grinned before saying " _It runs in the blood. Koenma said that probably we would have never known about each other if something hadn't happened to her._ "

Kuwabara sensed the sorrow in Yusuke's words first " _What happened?_ "

" _She was to fight a vampire of their master class and she was going to die according to a prophecy._ "

" _But she lived right? She beat him?_ " asked Kuwabara nervously remembering Yusuke's reactions to losing his friends and Keiko; they didn't need him going off the deep end again.

" _No, she died for a couple of minutes…drowning…lucky a friend of hers performed CPR and brought her back. Then she faced the vampire again and killed him. That was the same night as the party._ "

Kuwabara's eyes went wide and said in surprise " _That's what you were reacting to that night!_ "

Yusuke nodded and said " _Koenma described it as her soul was damaged, in part from being brought back as a Slayer despite the line moving on to the next girl and in part due to the Hellmouth. In response, her soul sent out a cry through her bloodline for help. If the old man was still alive then he would have felt it too and mom should have felt it._ "

Kurama smiled and said " _Looks like coming back from the dead also runs in the blood for your family._ " Then he said more seriously " _There something else, isn't there?_ "

" _Her stepmother doesn't know about her being the Slayer. When Buffy, yes that's her name, tried to tell her before, she put Buffy in an insane asylum until Buffy recanted. Lucky Buffy is still living with her instead of her biological father, the bastard._ "

" _Not only did he abandon mom and me and kidnapped my little sister, but then he abandon her and her stepmother to run off with his secretary. He also agreed to put Buffy in the insane asylum._ "

" _What's the plan, Urameshi?_ " asked Kuwabara

" _Fix what I can and make sure she is as safe as she can be and explain who she is, what we are. And beat the heads of anyone who gets in my way._ " Yusuke ended his statement with a grin

The rest of the group grinned in response and Kurama said " _Sounds like a plan. Do you need our help?_ "

Yusuke shook his head stating " _Not right now, just look after Keiko while I'm gone. She knows why I'm going and would be going with me if it wasn't for the danger. I'm not about to risk her or the baby._ "

Hiei asked " _When do you leave?_ "

" _Tomorrow morning by plane. Koenma said something about it being more legal to do so than taking a portal._ " replied Yusuke

" _I'll be gone for at least a week if not more but if there's an emergency Botan knows to come and get me by portal._ "

" _Don't worry about things here Urameshi._ " stated Kuwabara " _Just help out your sister._ "

" _The oaf is right for once._ " said Hiei, his only acknowledgement of the importance of the situation.

" _If you need any help or information, call us._ " stated Kurama

Yusuke smiled in relief and said " _Thanks guys and I'll be making arrangements for her to come here for the summer._ "

" _I've got to get back and finish packing._ " Yusuke said as he turned to walk away.

" _Later Urameshi._ " stated Kuwabara, heading to the train station to go back

" _Goodbye Yusuke._ " replied Kurama, going the same direction to catch a different train

Hiei vanished quietly into the surrounding woods as usual.

* * *

-Time skip-Just outside of Sunnydale, CA-

' _ **So this is Sunnydale.'**_ thought Yusuke as he drove past the sign welcoming him and into town looking for the high school

' _ **There it is.'**_ He finally spotted it and pulled into a visitor's parking spot.

' _ **The report stated her Watcher is the librarian so I'll start there.'**_

Yusuke walked into the school and was looking for the library when he ran into Principal Snyder.

Snyder sneered and snidely said "Shouldn't you be in class Mr…?"

Yusuke glared at the little troll who flinched badly in response and said "No, I'm looking for Mr. Rupert Giles."

Snyder now scared from the force of Yusuke's glare stammered "He's in the library, first door on the right down that hall."

Yusuke smirked and said "Thanks." as he headed down the hallway Snyder pointed to. Snyder turned and quickly walked back to his office to report to the Mayor about this new development.

Yusuke looked through the library door's windows before walking in. Giles had his back to the door.

"Can I help you with anything?"

"Yes, are you Mr. Rupert Giles?" asked Yusuke politely for once in his life

Giles turned around and noticed Yusuke looked too old to be a high school student.

"Yes, and who are you?" he asked in surprise

"I'm Yusuke Urameshi but I doubt you've heard of me before. Your Watcher's Council isn't very knowledgeable about true demons or spirit world after all." stated Yusuke matter-of-factly

Giles now worried about what Yusuke might be, moved toward his office praying that he would be fast enough to reach the weapons stored there if there was trouble.

Noticing this Yusuke continued "Don't worry I'm not here to hurt you. After all, you've been keeping my little sister safe."

Giles asked in confused "And just who is your little sister?"

Yusuke smiled wide and answered "Your Slayer, Buffy Summers or should I say Elizabeth Urameshi, daughter of Atsuko Urameshi and Hank Summers."

Giles did what any ordinary human would do in this situation, he passed out.

Yusuke caught him before he hit the ground.

"Wasn't expecting that reaction." He said as he placed Giles gently on the ground and sat down by him to wait for him to come around.

Giles woke up a couple minutes later and looked at Yusuke stating "It wasn't a dream or a hallucination then."

Yusuke smirked "Nope."

Giles sat up and asked "You're really Buffy's older brother? And you know about the Watcher's Council? And about Buffy being the Slayer?"

Yusuke nodded, saying as he stood up "And I know something that you don't know, but this isn't the place for that conversation."

Giles nodded and stood up as well, "My office then."

Just then Buffy walked into the library with Willow and Xander saying "What's up Giles? Patrol or training tonight?"

Then they noticed Yusuke and Buffy tried to backtrack but was interrupted by Giles "No, tonight is apparently going to be a family history lesson."

Yusuke smirked "That's correct. Starting with your real birth name, Buffy Summers."

Confused Buffy stated "But that is my real name."

Then she got suspicious and asked "Who are you?"

She moved to get between Yusuke and Giles "Another vampire hoping to bring back The Master? Sorry to say, but that's going to be a lot harder than you think. His bones are ashes now and you'll have to get to my friends through me first!"

Yusuke was confused "He tried to come back?" Then angry "Where is he?"

Giles, still unsure what Yusuke was, quickly defused the situation calmly stating "He's still dead. After Buffy and Angel interrupted the ritual, Buffy destroyed his bones. It was last night, you just missed it."

Yusuke looked disappointed "Too bad, I was looking forward to teaching him not to mess with my family." Then he smirked at Buffy and said "Good job…little sister."

"Hold it. Time out." said Xander, making the time out signal of a 'T' with his hands "Buffy you had a brother and didn't tell us?"

Buffy glared at Xander and said clinched her teeth "I don't have a brother."

Yusuke, still smirking, stated "Yes you do. I'm Yusuke Urameshi and I'm your older brother, Elizabeth Urameshi."

Buffy now angry tried to punch Yusuke saying "My name is Buffy Summers."

Yusuke easily caught her fist and stated "That's what your name was changed to when your biological father Hank Summers, married Joyce your stepmother after kidnapping you and abandoning me and our mother in Japan."

Buffy, in shock partly from how easily Yusuke caught her fist and partly from the information, asked "What?"

Giles, cleaning his glasses, calmly said "I'll call Mrs. Summers here. Xander, Willow if you will join me in my office for a moment…?"

Willow understanding Giles was trying to give the newfound half-siblings some privately, elbowed Xander saying "Of course Giles. We're right behind you."

"Ow! I meant yeah, right behind you." stated Xander

The three of them quickly walked into Giles's office, Giles saying before he closed the door "Buffy, remember we are here if you need us."

The moment they were out of sight, Yusuke pulled Buffy into a hug saying " _It's ok, imouto. Nii-san is here now._ "

In that moment, Buffy felt her soul shift and sigh in relief. She broke down crying, finally feeling safe for the first time since that horrible night.

Yusuke comforted her until she was able to stop crying.

Buffy looked up at him with tear-filled eyes and asked one simple word "How?"

Yusuke smiled sadly and answered "When you were brought back, your soul was hurt. It sent out a cry for help to your bloodline, our bloodline. I heard you but didn't realize what it was until a couple of days ago. Otherwise I would have been here much, much sooner."

Buffy hugged Yusuke again before letting him go and reaching for the box of tissues on the counter.

"I believe you. I don't know why but I believe you."

"As someone I know once said "Blood always knows blood.""

(Author's note: This is not an actual quote as far as I know. Just something I can imagine Raizen saying at some point during Yusuke's time in demon world to him.)

"Who said that?"

Yusuke smirked and said "I'll tell you later. The important thing is that you believe me and that you know you've got back-up."

Buffy nodded as Willow opened the office door and said "Mrs. Summers is on her way here."

Yusuke replied "Good. It's time she got the full story and I'll tell my story afterwards."

Joyce arrived ten minutes later and quickly walked through the library doors.

Spotting Buffy immediately, she didn't see anything wrong, "What is going on? Buffy are you alright?"

Yusuke responded to her first "Hello, Mrs. Summers. I'm Yusuke Urameshi."

Joyce looked puzzled for a moment before a look of recognition appeared on her face. "Urameshi? Hank's first wife's last name?"

"They didn't exactly get married but I'm not surprised he told you they did and I bet he told you that he got custody of Elizabeth, right?" At Joyce's nod, Yusuke continued "He didn't. He is wanted for kidnapping in Japan."

Joyce weakly said "What?" as she nearly collapsed

Giles and Buffy quickly walked her to a chair before she actually collapsed.

Joyce quickly regained her composure and asked "What exactly are you doing here, Mr. Urameshi?"

"Call me Yusuke." Yusuke stated first before answering her question "Getting to know my sister, Mrs. Summers, and to help her out."

"Help her out with what?" asked Joyce still confused

Yusuke looked at Giles, then Buffy and said "You need to tell her everything."

Buffy nodded, took a deep breath and said "Mom, I'm the Vampire Slayer."

Joyce sighed and said "Buffy, not this again. Vampires don't exist. They…"

Giles interrupted her "They do exist."

And Giles told her the whole 'The World is older than you know' speech and what Buffy is.

(Author's note: I'm skipping over this part because this speech is very well known to anyone who has even just watched a couple of episodes of the show.)

After Giles tells Joyce, the whole 'The World is older than you know' speech.

Yusuke looked slightly surprised and said "So that's what they tell you or what they believe."

Giles raise an eyebrow and asked "You have something to add?"

Yusuke smirked "Yes, that story is partly incorrect. In truth, there are three worlds: Spirit World, Human World, and Demon World. After a few centuries, demons from Demon World decided to see what Human World had to offer and found out there were as they put it intruders from other dimensions running around. The demons were very upset; believing that as Human World is a part of the dimension they belong to it was theirs and everything in Human World. According to legend, they along with the Slayer forced out the intruders for the most part. Nearly all demons today believe that the Slayer is a myth. More time pasted and humanity started to make a comeback. Some demons liked this and some demons didn't. Eventually Spirit World got involved and banished the higher level demons back to Demon World and put a barrier in place to keep them there. However, they couldn't keep all of the demons there so Spirit World did its best to keep Human World safe from the demons who made it through the barrier to here. One day, they decided to appoint a human high in spiritual power to be what they called 'The Spirit Detective'." At this point, Yusuke turned to Buffy and said "Basically your job but on a bigger scale." He continued "Eventually I became the Spirit Detective as part of a deal to be brought back to life after I died saving a kid's life…" (insert Yusuke's adventures here)

Skipping ahead about three hours, "…That was when I found out something about our bloodline, Buffy."

Buffy was on the edge of her seat and asked quietly "What was that?"

Yusuke took a deep breath and said "About 700 years ago, our ancestor slept with a demon known as Raizen. He was a Mazoku, a special type of elite and powerful demon. He was a demon who ate humans until he fell in love our ancestor. Together they had a child but he was forced to leave to protect her and the yet to be born child. He swore to her that he wouldn't eat another human until he saw her again. However, the barrier between the worlds was put up before he saw her again. 44 generations later, there we are. Now with Mazokus, those in the bloodline must prove themselves worthy of the bloodline before they get its power. For me, that moment came after I died a second time trying to stop the former Spirit Detective from opening a portal between Demon World and Human World and letting all of the demons out…"

He was interrupted by everyone shouting "WHAT?!"

"I'm part demon? You're a demon? Am I evil? Are you evil?" Buffy was breaking down again from shock as everyone else was too far in shock to say anything more. Yusuke quickly moved to reassure Buffy.

"You are not evil. I'm not evil." He said firmly and calmly "I'm a half-demon by popular opinion but technically nearly 99% human just as you are. The only difference is my demon blood is awake and active while yours is technically partly awake."

Buffy took a hold of those statements and forced herself to calm down. Noticing Buffy calming down, Yusuke told her "We'll talk more about this later, ok _imouto_?"

Buffy nodded.

Yusuke took that as his cue to finish his life story. Skipping ahead another couple of hours, Giles was the first one to speak after Yusuke had finished his story "Interesting…"

This statement caused the three teens in the room to break down laughing, one thing they had learned over the last few months was Giles tended to say that when he couldn't think of anything else to say. Their laughter eased the tension that had been gathering in the room.

"So, what is going to happen now?" asked Joyce who was still trying to accept everything that she had been told tonight from the fact that her daughter was the Slayer and that demons exist to meeting her daughter's half brother.

"You do know that Buffy can't just move to Japan, don't you? She is still needed here as both the Slayer and as herself." spoke Giles

Yusuke nodded "I know that but during the summer I'm hoping Buffy and Joyce won't mind coming to Japan for a visit."

Buffy and Joyce beamed with joy, Buffy for the fact that she would be getting to know more about her family and Joyce for the fact that her daughter, blood or not, was staying with her.

"I'll also be staying in town for at least a week."

"You must stay with us." Joyce was quick to offer

Buffy chimed in with her two cents "It would be safer than you staying in a hotel. Just because vampires are no threat to you, doesn't mean they won't try to hurt you."

Yusuke looked at her in surprise "The vampires around here are really that dumb?"

At everyone's, besides Joyce, nod, Yusuke laughed and said "Alright."

Giles stated "Then that is settled. Buffy, take the night off and I'll see you back here for training before patrol tomorrow night. Xander, Willow I'll give you two a ride home tonight. Yusuke, it was nice meeting you if you could drop by tomorrow I would like to talk more about this Demon World and Spirit World. Joyce, if you have more questions regarding information about Slayers let me know. Otherwise I think it is best we leave for the night."

That was when everyone else noticed the time was 1 am which was not a big deal for the Scooby Gang or Yusuke normally speaking, but they knew it was better to leave before Snyder found them out. Everyone said their goodbyes for the night and separated to leave. Joyce was walked to her car by Yusuke while Buffy walked Giles, Xander, and Willow to Giles's car. Joyce gave Yusuke directions while they waited for Buffy at Joyce's car. Regardless of these directions, Buffy decided to ride with Yusuke to make sure he didn't get lost and so they could talk some more about their demon heritage. Later, when they were all trying to sleep they wondered what surprises would the next day hold.

* * *

-Elsewhere in Sunnydale-

"Did you get his name?" asked Richard Wilkins III, The Mayor of Sunnydale into his office phone.

"No, sir." replied Principal Snyder through the phone

The Mayor paused in thought before saying "Thank you for alerting me to this potential problem. I'll have my people check it out. Keep up the good work."

"You're welcome sir! I will." said Snyder before the Mayor hung up

The Mayor turned in his chair to face his guest.

"Well it sounds like there is a newcomer in town. Please give him the welcome wagon."

The vampire known as Mr. Trick smiled and said "Of course. I'll have my people look around for …"

"No name. Just a description of a young adult male with black hair, brown eyes, and Asian-like features."

Mr. Trick nodded "Can't be too many newcomers to Sunnydale with that description."

* * *

Nami: I have finally started to break through my writer's block! I'm sorry to everyone who reads my other stories for the long wait, but I hope to have two new chapters posted for Triple Trouble by the end of the year. And I hope everyone is enjoying this new story. Just to explain something, I know Mr. Trick doesn't show up until after Faith does and he is working for Kakistos at the time. However I'm going with the idea that he was already working for the Mayor at the time and was showing Kakistos around on the Mayor's orders. Please read and review!

And a big "Thank you" to my beta-reader for this story, mcstrategist!


End file.
